Thursday, June 4, 2009

looking after your eyes

Looking after your eyesYou may not associate exercise and non-smoking with good eye health, but a healthy lifestyle can play a vital role in keeping your eyes healthy and maintaining good vision.Here is a guide to how and why lifestyle choices affect your eyes, with advice from Dr Frank Eperjesi, the director of the optometry undergraduate programme at Aston University.Nutrition, diet and exercise

Obesity is a major contributing factor to sight loss. It is estimated that the 10 million adults and two million children in the UK who are obese are twice as likely to lose their sight.A report published by the RNIB (Royal National Institute of Blind People) identified a direct link between obesity and some of the common eye conditions that cause blindness. These are:Age-related macular degeneration (AMD) AMD is the most common cause of adult blindness in the developed world. The macula is the central part of the retina at the back of the eye, and is responsible for picking up detailed visual information, such as reading words on a page, or sewing. It wears out naturally as we get older, resulting in poorer vision. Obesity speeds up the onset of AMD, and there is little treatment for the condition.

Diabetic retinopathy Obesity significantly increases the risk of developing type 2 diabetes. Someone with a body mass index (BMI) above 35 is up to 80 times more likely to develop the condition than someone with a BMI of less than 22. The most serious eye condition associated with diabetes involves the retina and, more specifically, the network of blood vessels within it. The vessels can allow fluid or blood to leak into the retina and damage it. This can result in serious loss of vision. (See video below)

Cataracts A cataract is a gradual thickening that develops in the lens of the eye. If you're obese, the risk of developing cataracts can be double that of people who are not overweight. Although cataracts are largely treatable, one in four cases of sight loss in people over the age of 75 is due to cataracts.

NutritionStudies show that antioxidants prevent the retina from damage done by smoking, alcohol and ultraviolet rays. As we age, the body is less efficient at getting rid of oxidants, and this can cause retinal damage.

An antioxidant called lutein is hugely beneficial. "Lutein is a protection factor," says Dr Eperjesi. "It absorbs harmful wavelengths of light and behaves as a powerful antioxidant. However, the body does not produce its own lutein, so for this protection system to work effectively we need 6-10mg a day."

It is estimated that the average western diet contains only 2-3mg per day, which means most of us lack lutein in our food. This is thought to be one of the reasons why macular degeneration has become more common.

Lutein is found in broad-leaf leaves such as spinach and kale, and in yellow vegetables such as sweetcorn and yellow peppers. But it is not just these vegetables that Dr Eperjesi recommends. "Evidence suggests that a diet rich in brightly coloured fruit and vegetables in general is good for antioxidants," he says. "And I'd say that five a day should be the bare minimum."Finally, what about the widespread belief that carrots are good for your eyesight? "That's folklore, really," says Dr Eperjesi. "There is no protective element and they are low in lutein, but they do contain beta-carotene which, when converted to Vitamin A, is important for eye function."

AlcoholDrinking alcohol is not necessarily bad for your eyes. "Alcohol destroys antioxidants in the body," says Dr Eperjesi, "but the red pigment in red wine is a powerful antioxidant, so there are suggestions that drinking a glass of red wine in the evening won't do any harm in terms of macular degeneration. If you drink too much, however, the positive effects of the pigment will be outweighed by the negative effects of the alcohol."

ExerciseWhile it might seem odd that exercise can help the eyes, it can be important. "Good cardiovascular function is important, as poor circulation affects the blood vessels in the eyes," says Dr Eperjesi. Research shows that exercise may reduce the risk of sight loss that can occur from high blood pressure, diabetes and the narrowing or hardening of the arteries.Smoking"After ageing, smoking is the biggest risk factor for developing macular degeneration," says Dr Eperjesi. Research shows that smokers are three to four times more likely to develop AMD compared with non-smokers.

As well as AMD, smokers are about three times more likely to develop cataracts, a major sight-threatening condition.Scientists believe that smokers may be more susceptible because metals found in tobacco smoke can gradually build up in the eye. Whatever the reason may be, the risk of developing a cataract increases the longer and more heavily a person smokes.

Aside from these serious, sight-threatening conditions, smokers are also more likely to have problems if they wear contact lenses. Their corneas run a greater risk of getting irritated, which can seriously affect vision if they subsequently become infected.The good news, however, is that all these risks start to drop as soon as you stop smoking, and they decline steadily the longer you don't smoke.

The sunProtecting your eyes from the sun is very important and should not be underestimated. Under no circumstances should you ever look at the sun directly. Doing so could do irreversible damage to your eyesight and even lead to blindness. Sunlight can damage the retina and the lens of the eye, and studies show that people with outdoor jobs are more likely to suffer eye problems.The College of Optometrists recommends buying good quality, dark sunglasses (these needn't be expensive). Look for glasses carrying the 'CE' mark and the British Standard BS EN 1836:1997, which ensures that the sunglasses offer a safe level of ultraviolet protection.

Regular eye examinationsIt is recommended that you visit an optometrist every two years (or more frequently if advised). This is important because an eye examination can detect potentially blinding eye conditions such as glaucoma, or underlying health problems such as diabetes. The earlier the problem is detected, the faster it can be treated.It is easy to neglect your eyes because they rarely hurt when there is a problem. But once your eyesight is lost, it may never be restored.

Videos: glaucoma & diabetic retinopathyWatch a consultant ophthalmologist describe how diabetes can affect your vision and the possible treatments.Also, watch a consultant ophthalmologist explaining what glaucoma is, how it can affect your vision and how it can be treated.